1. Field of the Invention
The present invention relates to the field of ventilation and air treatment and conditioning equipment and in particular relates to the field of commercial dishwashing equipment.
2. Description of the Prior Art
Some dishwashing apparatus use one form or another of air drying to dry dishes within the apparatus during the appropriate drying cycle. It has long been appreciated that the air drying of dishes in a commercial dishwasher can be accelerated by increasing the temperature of air or water within the drying chamber. If dishes are continuously conveyed into the cavity on a conveyor-belt type dishwasher, some means is necessary to inhibit or prevent the escape of steam and vapors into the surrounding work spaces. It has long been appreciated that in addition to increasing temperatures in order to evaporate water from the dishes and to lower the relative humidity of the air, moisture laden air might later be cooled in order to induce condensation and to effectively dry the air for reuse during the drying cycle. One of the ways in which the prior art has sought to circulate and dry moisture laden air within a dishwashing chamber is shown in Karig, U.S. Letters Pat. No. 2,918,068.
Prior art dishwashing apparatus have employed comparatively inefficient means for isolating the dishwasher from surrounding work spaces and for drying the moisture laden air within the dishwasher cavity. The prior art has generally failed to address or deal with problems concerning air circulation through dishwashing cavity, or energy efficiency during the dishwashing operation. Typically, such dishwashers create an air flow through the cavity by drawing in large amounts of fresh make-up air in order to obtain the desired flow rate, preheating it, using it during the dishwasher operations and then exhausting substantially all of it to the outside environment. As a consequence, large amounts of treated air are drawn from the work space and lost to the outside environment. As disclosed below, the present invention has overcome each of these problems and inadequacies of the prior art.